After 3 weeks from submission, I recieved the below email from the editor in chief of an applied math journal, asking whether I would consider changing my manuscript from full length article to a letter/short article, giving primary reason that the article length is short, so it would suit a short article/letter, and mentioning that the journal publishes short articles of high quality along with full length articles in all regular issues. I was asked to give my decison. I had a look at the letters/short articles of that journal from previous issues and found that they are no different, except in length. So I am not understanding the difference.
I am not able to interpret, whether I have been strongly adviced by editor, and that I better go with it. The editor already had that article with him for 3 weeks, so he might have had a look at it and might be giving strong advice. I also don't fully understand the difference between both modes of publishing. Do these two have different academic values?
Dear Mr. XXXX,
I am writing to ask if you would consider to change your submission, XXXX, to a Letter from a Full Length Article. The reason for my request is based on the short length of you manuscript. XXXX Journal publishes short papers of high quality. Please let me know of your decision. The official review process will not proceed until we hear from you. Thank you.